The “Fundamentals of Network Security Companion Guide” is a comprehensive textbook published by Cisco Press as part of the Cisco Networking Academy Program Series. Written by the Cisco Networking Academy Program Staff, this hardcover book covers topics in networking and security, making it an essential resource for students and professionals in the computer subject area. With 912 pages filled with valuable information, this guide is a valuable addition to any library for those looking to deepen their understanding of network security principles.